What Is Photopolymerization in 3D Printing?


During operation, 3D printers often release heated material in a liquid or semi-solid state. Doing so allows the 3D printer to release an even and consistent amount of material, thereby reducing the risk of defects like ghosting. Finished objects, however, must be solid, which is where photopolymerization comes into play. Photopolymerization is used to harden the deposited material so that the finished object achieves a solid state.

The Basics of Photopolymerization

Photopolymerization is the curing process that’s characterized by the use of ultraviolet (UV) light. In 3D printing, it’s used to cure the deposited material. When exposed to UV light, the deposited material cures. Curing results in physical changes to the deposited material, turning it from a liquid or semi-solid state to a solid state.

Not all materials support photopolymerization. Rather, this curing process is used exclusively for photopolymer materials. A photopolymer material is a type of resin material that hardens under UV light. Other types of materials are generally unaffected by UV light. For photopolymerization to work, a photopolymer material must be used in the 3D printer.

How Does Photopolymerization Work?

Photopolymerization works by leveraging the UV-sensitive properties of photopolymer materials. For most 3D printing processes, layers of deposited material are cured via a UV light. After the 3D printer has completed a layer, a UV light is projected over it. The UV light triggers a reaction within the deposited material, essentially solidifying it. The cured material changes to a solid state, allowing for the production of a solid and finished object by the 3D printer.

Some of the most common 3D printing processes that support photopolymerization include the following:

  • Digital light processing
  • Continuous liquid interface production
  • Stereolithography

Benefits of Photopolymerization

Of course, there are other curing methods available for 3D printing materials. Some 3D printing processes use a laser, for instance. The laser moves across the top of the print bed while curing the underlying material. When compared to lasers, as well as other curing methods, photopolymerization offers several advantages.

Photopolymerization is highly effective at solidifying deposited materials. It’s able to change the physical properties of the deposited material so that it’s stronger and better protected against damage.

With photopolymerization, entire layers of deposited material can be cured at once. This is in stark contrast to laser-curing methods, which generally only cure a small section of material at once. Because it’s capable of curing entire layers at once, photopolymerization can be performed very quickly.

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